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A243037
Number of length n+3 0..n arrays with no four elements in a row with pattern abab (with a!=b) and new values 0..n introduced in 0..n order
1
7, 36, 163, 738, 3516, 17919, 97849, 570383, 3532239, 23132758, 159573602, 1155434411, 8755269880, 69244208899, 570254905607, 4879985079384, 43312872677674, 398041803812734, 3781687068799550, 37091840207913759
OFFSET
1,1
COMMENTS
Diagonal of A243044
LINKS
EXAMPLE
Some solutions for n=4
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....0....1....1....1....1....1....1....1....0....0....1....1....1
..2....2....2....1....2....2....2....0....2....2....0....0....1....1....2....2
..0....3....2....2....1....2....2....0....3....1....2....1....0....2....2....2
..2....4....3....1....0....2....1....1....3....3....3....0....2....3....3....1
..3....1....3....0....1....2....3....2....4....2....1....2....3....1....4....3
..2....1....2....0....1....0....3....3....4....3....3....0....4....3....3....2
CROSSREFS
Sequence in context: A097554 A055221 A080420 * A181292 A026018 A085354
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 29 2014
STATUS
approved